class Solution {
    public int romanToInt(String s) {
        int nums[] = new int[s.length()];
        for(int i = 0; i < s.length(); i++) {
            switch (s.charAt(i)){
                case 'M':
                    nums[i]=1000;
                    break;
                case 'D':
                    nums[i]=500;
                    break;
                case 'C':
                    nums[i]=100;
                    break;
                case 'L':
                    nums[i]=50;
                    break;
                case 'X' :
                    nums[i]=10;
                    break;
                case 'V':
                    nums[i]=5;
                    break;
                case 'I':
                    nums[i]=1;
                    break;
            }
        }
        
        int sum = 0;
        for(int i = 0; i < nums.length - 1; i++){
            if(nums[i] < nums[i + 1]) {
                sum -= nums[i];
            }   
            else {
                sum += nums[i];
            }
        }
        
        return sum + nums[nums.length - 1];
    }
}
